This disclosure is directed to archery and more particularly to a unobvious arrow construction. The significance of this construction is best understood in describing the instantaneous loading that occurs in launching an arrow. Consider the traditional bow, and assume that it is a bow requiring about 50 pounds of pull. The bow string is placed in the arrow nock. On release, there is an instant at which 50 pounds of loading is applied to the arrow. At the time of release, the arrow is stationary. It is instantly struck from the arrow nock with the full force of the bow string. While the inertia of the arrow is being overcome, it is forced to move forward. An arrow is inherently a rigid body and does not have the ability to absorb the impact. That is, it is lacking the ability to compress and absorb energy in the fashion of a baseball or golf ball. Promptly after release of the arrow, the load on the arrow begins to drop rapidly. Thus, the force which is applied to the arrow is relatively unevenly distributed. The peak of the force is applied at the instant of release. As the bow string pushes the arrow forward in the first small portion of movement, the force drops off rapidly so that the best description of force applied to an arrow from a conventional bow is more of an impulse.
The compound bow has become popular lately. For a compound bow with a nominal 50 pound rating, the 50 pound peak occurs after some measure of arrow movement. The initial loading is reduced, perhaps about 70% of the peak loading. During arrow movement from the cocked position as the arrow is launched and as the compound bow operates in its peculiar fashion to supply power in its different loading, there is some benefit in redistributing the energy impulse delivered to the arrow by the compound bow. However, this still does not overcome the problem which exists in the fact that an arrow is something of a rigid device at the time of launch and is shocked with an impulse.
When launch occurs, the arrow is loaded in the fashion of a column. There is a tendency of the arrow to bend or flex along its length without regard to arrow stiffness. As stronger bows are used, the bending or flexing simply increases. It is submitted that this type of bending resulting from impulse loading from a conventional bow or a compound bow is a cause of inaccuracy. That is, the bending or flexing of the arrow at the time of launch causes the arrow to deflect off course.
It is desirable to make the arrow something of a resilient body. While conventional arrows are perhaps thousands of years old, recent arrow designs have included U.S. Pat. No. 3,759,519. This disclosure sets out a telescoping arrow including an internal spring. Primarily, this structure enables the arrow to collapse for storage or transportation. Perhaps a similar device is a weight moved by internal upset action in a toy missile described in U.S. Pat. No. 3,181,269. A less pertinent is U.S. Pat. No. 3,021,139. Perhaps equally U.S. Pat. No. 3,586,332 is just as remote. A dart having an internal spring to enable tip breakaway is set forth in U.S. Pat. No. 4,109,915. It is submitted that the present structure represents a patentable advance over the structures shown in these references.